tbuckley/cabot-search huggingface dataset:
Abstract P2104: Branched-chain Amino Acids Are Required For Acquisition Of The Cardiac Myofibroblast Phenotype
Authors: Daniel C Nguyen, Collin Wells, Sujith Dassanayaka, Steven P Jones, Bradford G Hill
Journal: Circulation Research (2023)

Introduction: Branched-chain amino acids (BCAAs) are critical mediators of anabolic signaling and are essential for cell growth. Findings in both animals and humans indicate that intra-cardiac BCAA levels are markedly elevated in the myocardium after infarction. Nevertheless, it remains unclear how BCAAs contribute to processes involved in post-infarction cardiac remodeling, such as fibrosis. The goals of these studies were to evaluate whether BCAAs can regulate collagen production and facilitate myofibroblast transdifferentiation. Methods and Results: To determine how profibrogenic stimuli influence genes critical for BCAA uptake and catabolism, we performed bulk RNA sequencing on fibroblasts isolated from sham and post-infarcted hearts as well as from naïve fibroblasts treated with TGFβ. Compared with fibroblasts from sham hearts, fibroblasts from post-infarcted hearts had higher expression of BCAA transporters ( Slc7a8 , Slc3a2 , Slc38a1 , Slc1a5 ), lower levels of the inhibitory kinase Bckdk , and higher levels of Bckdh complex constituents ( Dbt, Dld ; n=3–6/group;,q&lt;0.05). Similarly, TGFβ elevated Slc3a and Slc38a1 as well as the BCAA catabolic gene, Bcat1 (n=3/group; q&lt;0.05). Culture of cardiac fibroblasts in BCAA-free medium completely prevented TGFβ-induced Col1a1 and periostin upregulation and markedly diminished α-smooth muscle actin abundance (n=3/group; p&lt;0.05). Conclusion: In cardiac fibroblasts, profibrogenic stimuli increase the expression of genes involved in BCAA uptake and catabolism. BCAA availability significantly impacts fibroblast activation by regulating collagen synthesis and myofibroblast transdifferentiation. Ongoing studies will elucidate whether BCAA catabolism contributes to myofibroblast activation and whether lower dietary BCAA levels influence cardiac remodeling after myocardial infarction.
Abstract P2124: Trans-valvular Unloading Protects Against Post-reperfusion Injury Via Hif-1a In Preclinical Models Of Acute Myocardial Infarction.
Authors: Lija Swain, Lara A Reyelt, Xiaoying Qia, Shreyas Bhave, Kay Everett, Elena Mahmoudi, Monica Majumdar, Mary Warner, Navin K Kapur
Journal: Circulation Research (2023)

Acute myocardial infarction (AMI) is a major cause of heart failure and mortality worldwide. Reducing left ventricular (LV) workload using a trans-valvular pump (TVP) and delaying reperfusion for 30 minutes reduces infarct size by 50% in preclinical models and is currently under clinical investigation. We hypothesized that LV unloading limits myocardial injury by activating hypoxia inducible factor 1-α (HIF-1α). Myocardial ischemia was induced by percutaneous balloon occlusion of the left anterior descending (LAD) artery for 90 minutes in adult male swine. The detailed study design is shown in Fig A. In Group A and B, no infarct was observed with or without TVP. In Groups C and D, infarct size was significantly lower with TVP activation (Fig B). During LAD occlusion without reperfusion, HIF-1α levels increased within the infarct zone (Group A), but were significantly lower with TVP activation (Group B). After reperfusion, HIF-1α levels decreased in Group C, but paradoxically, increased with TVP support (Group D; Fig C). To test whether HIF1α mediates cardioprotection with LV unloading, adult swine were treated with intracoronary delivery of a HIF-1α inhibitor (2-methoxyestradiol; 2ME) before reperfusion. Compared to DMSO-treated controls, 2ME increased infarct size despite LV unloading (Fig D). Conversely, compared to reperfusion alone, intracoronary delivery of a HIF-1α stabilizing agent (Roxadustat) before reperfusion significantly decreased infarct size both in the presence and absence of a TVP (Fig E). We identified a novel functional role for HIF-1α as a critical mediator of the cardioprotective effects associated with trans-valvular unloading before reperfusion.
Abstract P2146: Endothelial Cell Specific Senescent Cell Clearance Alleviated Vascular Stiffness And Metabolic Dysfunction In Obese Mice
Authors: Masayoshi Suda, Runqing Huang, Carolyn M Roos, Luisa Leon, Utkarsh Tripathi, Jordan D Miller, Tamar Tchikonia, James Kirkland
Journal: Circulation Research (2023)

Aging is the leading predictor of acquired cardiovascular disease (CVD), and emerging evidence suggests cellular senescence plays a causal role in development of clinically-significant CVD. While we previously reported that senescent cell elimination delays or prevents progression of several aging phenotypes in aging mice, the responsible types of senescent cells contributing to cardiovascular dysfunction in vivo are not yet elucidated. To test the hypothesis that senescent endothelial cells are a major contributor to cardiovascular dysfunction, we developed Tie2-Cre; p16 Ink4a - LOX-ATTAC mice, which allows for specific elimination of p16 Ink4a+ senescent endothelial cells upon administration of AP20187 (which only affects cells carrying the conditionally-expressed ATTAC construct). Using a mouse model of diabetic vascular disease (40% fat diet for 12 weeks , HFD), we found that biweekly selective removal of senescent endothelial cells alleviated HFD-induced endothelial dysfunction in aorta (assessed ex vivo using isolated organ baths). Additionally, ejection fraction (assessed using in vivo echocardiography) was preserved in AP20187-treated mice (driving ATTAC-dependent removal of senescent endothelial cells) compared to their vehicle-treated controls (76.6%±4.2, 63.2%±4.2). In addition to improvement in cardiovascular function, metabolic parameters (HbA1c and fasting glucose levels) were improved by senescent endothelial cell elimination. Collectively, these data suggest that elimination of p16 Ink4a+ senescent endothelial cells may be a viable therapeutic strategy for alleviation of metabolic disease-induced cardiovascular dysfunction.
Abstract P1109: DNA Damage-free iPS-Cardiomyocytes Reduces Cardiac Fibrosis
Authors: Jessica Miller, Prasanna Krishnamurthy, Palaniappan Sethu, Ramaswamy Kannappan
Journal: Circulation Research (2023)

With the increasing potential of employing cardiomyocytes (CMs) derived from human induced pluripotent stem cells (iPSC) in myocardial repair, there is a demand for a method of reducing the induction of fibrosis at the transplantation site. We hypothesized that transplantation of anti-inflammatory DNA damage-free CMs (DdF-CM) could reduce fibrosis formation at the implantation site. The transcription factor, p53, is inflammation-dependent: influencing apoptosis in inflammatory or damaged cells and promoting proliferation in normal cells. Previously, we demonstrated that the p53 activator nutlin-3a could prime hiPSC culture to contain only DdF-iPSCs by inducing apoptosis in DNA-damaged inflammatory cells and successfully differentiated them into DdF-CMs. Further investigation into these cells revealed that DdF-CMs secrete exosomes containing miR-26a. These miR-26a exosomes are up-taken by host fibroblasts, reducing collagen I secretion around the graft site and overall scar size formation post-MI. Additionally, DdF-CMs transplanted mice demonstrated improved cardiac function and cell engraftment after 4 weeks post-MI. This study illustrates that transplanting DdF-CMs into infarcted hearts improves cardiac function and reduces fibrosis formation at the implantation site.
Abstract P3117: Cardiac Proteomics Analysis Reveals Sex-related Differences In Doxorubicin-induced Delayed Cardiotoxicity
Authors: Ibrahim Y Abdelgawad, Benu George, Marianne Grant, Yingbo Huang, Yuting Shan, R. Stephanie Huang, Beshay Zordoky
Journal: Circulation Research (2023)

Introduction: Cancer survivors experience long-term cardiovascular complications due to chemotherapeutic drugs such as doxorubicin (DOX). Sex was shown to be an important risk factor for DOX-induced cardiotoxicity. Previous proteomic studies characterized the immediate cardiotoxic effects of acute or chronic DOX in male mice, but no proteomic studies have been conducted in DOX-treated female mice. In the current study, we first characterized sex differences in DOX-induced delayed cardiac dysfunction using a mouse model and then identified the proteomic changes associated with the observed sex differences. Methods: Five-week-old male and female mice were administered intraperitoneal injections of DOX (4 mg/kg/week) or saline for six consecutive weeks. Echocardiography was performed five weeks after the last dose of DOX to evaluate cardiac function. One week later, all mice were sacrificed and hearts were collected for further analysis. Gene expression of cardiac stress markers was assessed by PCR. Proteomic profiling of the heart from both sexes was undertaken to determine the differentially expressed proteins (DEPs). Results: DOX-treated male, but not female, mice showed cardiac dysfunction with decreased cardiac output, ejection fraction, fractional shortening, and stroke volume. Additionally, only male mice demonstrated cardiac atrophy, lower left ventricular mass, and upregulated Bnp and β- Mhc expression. Proteomic analysis identified a total of 2461 proteins (FDR=1%), of which 29 and 46 proteins were up- and down-regulated in males, whereas 35 and 28 were up- and down-regulated in females. Enrichment of DEPs revealed that biological processes such as catalytic activity and response to topologically incorrect protein were downregulated in male mice, while many DOX-associated protective mechanisms were enriched in female mice. Conclusions: This is the first study to determine proteomic changes in a male and female mouse model of DOX-induced delayed cardiotoxicity. Our study demonstrates that male mice are more susceptible to DOX-induced delayed cardiotoxicity. Proteomic analysis identified several sexually-dimorphic DEPs, which could be important molecular targets in DOX-treated cancer survivors following further validation.
Abstract P2143: New Rock Inhibitor Improves Pulmonary Vascular Resistance And Right Ventricle Function In Animal Model Of Pulmonary Arterial Hypertension
Authors: Gisele Zapata-Sudo, Tadeu Montagnoli, Jaqueline S Da Silva, Bruna Rocha, Bianca Santos-Carlos, Carlos Fraga
Journal: Circulation Research (2023)

Pulmonary arterial hypertension (PAH) is characterised by increased pulmonary arterial pressure and vascular thickening, which causes RV dysfunction and failure. Current therapies lack efficacy for preventing disease progression and lead to poor survival rate in patients. Rho-activated protein kinases (ROCK) play a key role in smooth muscle contraction and proliferation and cardiomyocyte hypertrophy and survival, which indicate the potential of ROCK inhibitors to treat PAH. This work aims to assess the efficacy of a novel ROCK inhibitor, named LASSBio-2065, on cardiac and vascular function in monocrotaline (MCT)-induced PAH. Intraperitoneal injection of 60 mg/kg MCT induced PAH in Wistar rats, which protocol was approved by the Animal Care and Use Committee at Universidade Federal do Rio de Janeiro. After 2 wks, echocardiography confirmed the PAH and rats were randomly divided in groups and treated with either vehicle or LASSBio-2065 (60 μmol/kg/day, i.p.) for 14 days. At the end of treatment, hemodynamic parameters were evaluated using echocardiography and RV catheterization. Tissues were collected for histologic and morphometric analysis. Data expressed as mean ± SEM was analysed using One-way ANOVA followed by Dunnett post-test. LASSBio-2065 improves pulmonary vascular resistance and RV afterload because the ratio of pulmonary acceleration time-to-total ejection time reduced from 26.7 ± 2.0 to 21.7 ± 1.6 (p&lt; 0.05) and RV output from 64.2 ± 6.1 to 39.1 ± 8.0 (p&lt;0.05). Vascular and cardiac remodelling were prevented by LASSBio-2065, since medial wall thickness of distal pulmonary arterioles reduced and short axis RV-to-LV internal area increased from 85.8 ± 11.4 to 115.2 ± 17.8 (p&lt;0.05). The new ROCK inhibitor also improved the RV diastolic function, restoring both RV end-diastolic pressures increasing from 5.3 ± 0.8 to 11.1 ± 1.9 mmHg (p&lt;0.05) and Tau from 16.9 ± 2.2 to 27.1 ± 2.8 (p&lt;0.05). In conclusion, LASSBio-2065 significantly improved RV function in MCT-induced PAH. In conclusion, the new ROCK inhibitor represents a potential alternative for management of PAH-associated RV dysfunction and remodelling.
Abstract P1122: Ablation Of PDGFR&amp;#946; Expression In Cardiac-resident Mesenchymal Stem Cells Prevents Adverse Cardiac Remodeling In Chronic Heart Failure
Authors: Tariq Hamid, Mohamed Ameen Ismahil, Wei Liu, Yujie Zhu, Michael Katsnelson, Lina Ma, Mengya Mark, Gregg Rokosh, Sumanth D Prabhu
Journal: Circulation Research (2023)

Failing hearts exhibit chronic inflammation and progressive fibrosis. We recently reported temporal expansion and a pro-fibrotic role of Sca1 + cardiac mesenchymal stem cells (cMSCs) in chronic heart failure (HF), that was in part related to their increased expression of platelet derived growth factor (PDGF) receptor beta (PDGFRβ). PDGF signaling is mediated by two distinct receptors; -alpha (PDGFRα) and PDGFRβ. Whereas PDGFRα is considered a MSCs marker, the specific role of cMSC-localized PDGFRβ in failing hearts is unknown. We hypothesized that augmented cMSC-PDGFRβ expression in chronic HF promotes maladaptive LV-remodeling, fibrosis, and inflammation. We generated Sca1 +/MerCreMer -PDGFRβ f/f transgenic mice (Tg) with Sca1-directed inducible ablation of PDGFRβ expression. Littermates without Cre expression were used as controls. In our preliminary studies, following 2 w of permanent coronary ligation, mice (7-10/group) were fed tamoxifen-containing chow for 13 w. Echocardiography revealed that at 13 w, control mice had significant LV dilatation (ESV 117 ± 59 vs. 64 ± 37.6 μL; EDV 154 ± 69 vs. 87 ± 41 μL) whereas, LV dilatation in Tg mice was stabilized (ESV 78 ± 38 vs. 69 ± 18 μL, EDV 112 ± 42 vs. 92 ± 22 μL), with enhanced cardiac function (EF 32 ± 12 vs. 22 ± 7%). Analysis of changes in ESV, EDV, and EF revealed significantly smaller ΔESV, ΔEDV, and increased ΔEF, in Tg mice. Gravimetric data indicated Tg mice with significantly decreased normalized heart, spleen, and wet lung weights, all indicative of attenuated HF progression. Flow cytometric assessment of inflammatory responses indicated a significant decrease in; 1) circulating Ly6c hi monocytes, 2) total myocardial MHCII + F4/80 + macrophages, and, 3) F4/80 + CCR2+ infiltrating macrophages in Tg mice. These effects in Tg mice occurred together with a significant decrease in remote zone fibrosis (2 ± 2 vs. 9 ± 8%) and myocyte hypertrophy (422 ± 62 vs 527 ± 34 μm 2 ). We conclude that ablation of cMSC-PDGFRβ expression in post-infarction HF has beneficial effects that may be attributed to attenuation of LV-remodeling and dysfunction and a subsequent contraction of both systemic and myocardial inflammation. Modulation of PDGFRβ expression could thus be exploited as a therapeutic intervention in chronic HF.
Abstract P1105: Dissecting The Roles Of Vegfba And Pgfb In Zebrafish Cardiac Regeneration
Authors: Zhenyu Wang, Didier Stainier
Journal: Circulation Research (2023)

Vascular endothelial growth factor (VEGF) family members promote angiogenesis, regulate inflammation, antagonize oxidative stress, and regulate lipid metabolism, which present potential therapeutic value for coronary heart disease. However, all of their roles during cardiac regeneration are still largely unknown. Unlike mammals, zebrafish are able to fully regenerate their heart after injury. In zebrafish, Vegf factors are regulated in different manners after cardiac cryoinjury, indicating functional diversity during cardiac regeneration. Here, we focus on vegfba and placental growth factor b ( pgfb ), which have been much less investigated in regenerative contexts, and were found to be persistently down-regulated in injured hearts before 5 days post cryoinjury (dpci) according to our previous dataset. We generated HOTcre transgenic lines to control the overexpression of vegf genes in a spatially and temporally restricted fashion during cardiac regeneration. Global overexpression of vegfba had no significant effect on coronary vessels, whereas it promoted the proliferation of cardiomyocytes at 7 dpci. In addition, global overexpression of pgfb significantly increased the vessel coverage in the wound at both 96 hpci and 7 dpci. These results suggest their possible roles in promoting myocardial regeneration and revascularization. However, myocardium-specific overexpression of vegfba and pgfb significantly reduced coronary vessel coverage within the injured area and decreased the proliferation and dedifferentiation of cardiomyocytes, indicating possible disruption of revascularization and regeneration caused by their misexpression. To further study the mechanism underlying these phenotypic differences, we are performing transcriptomic analysis to identify the differentially regulated genes and related signaling pathways. This project will provide new candidate cues that may help understand the mechanisms of coronary revascularization and cardiac regeneration in zebrafish, with potential therapeutic implications of achieving better directed and enhanced regeneration upon coronary heart disease.
Abstract P2023: Mitogen-activated Protein Kinase-directed Modulation Of The Non-sarcomeric Actin Cytoskeleton In Cardiomyocytes
Authors: Kelly M Grimes, Stephanie L Bowers, Casey O Swoboda, Douglas P Millay, Jeffery D Molkentin
Journal: Circulation Research (2023)

A better understating of the mechanisms by which cardiomyocytes grow in different directions could open up new therapeutic avenues for hypertrophic and dilated cardiomyopathies, diseases that include the widening and lengthening of cardiomyocytes, respectively. Mitogen-activated protein kinase kinase 1 (MEK1) and extracellular signal-related kinases 1/2 (ERK1/2) are known to control this directional growth of cardiomyocytes, such that activated MEK1 causes concentric hypertrophy and cardiomyocyte widening, while genetic ablation of ERK1/2 proteins causes dilation and cardiomyocyte lengthening. To determine how these proteins may control this directional growth response, we conducted a phosphoproteomic screen using neonatal rat ventricular myocytes (NRVMs) treated with activated MEK1 adenovirus, U0126 MEK1 inhibitor, or control GFP adenovirus. The resulting data pinpointed over 2700 sites on 324 proteins as changing their phosphorylation status with modulation of this signaling cascade. Gene ontology analysis found that cytoskeletal-associated proteins were the largest subset of proteins with phosphorylation changes. Traditional and PhosTag western blots verified that many of these cytoskeletal proteins change expression as well as their phosphorylation status in NRVMs. In vivo experiments showed that cytoplasmic actin expression was upregulated in MEK1 transgenic or ERK1/2 gene-deleted hearts. Furthermore, MEK1 transgenic adult cardiomyocytes had enhanced cytoplasmic actin at lateral membranes. Palladin, an actin nucleating protein, changed both phosphorylation status and isoform expression in response to modulation of MEK1-ERK1/2 signaling. Adeno-associated viruses were used to overexpress different palladin isoforms. Immunostaining for these proteins showed that localization of palladin isoforms moved from the subcortical compartment to the sarcomere, suggesting these isoforms preferentially associate with either cytoskeletal or sarcomeric actin. Future studies will further examine the signaling roles that cytoplasmic actin may play in healthy and diseased cardiomyocytes and delineate preferential binding of actin associated proteins between cytoplasmic and sarcomeric actin in cardiomyocytes.
Recent advances in cancer-on-a-chip tissue models to dissect the tumour microenvironment
Authors: Kimberly Seaman, Yu Sun, Lidan You
Journal: Med-X (2023)

Abstract Three-dimensional cancer-on-a-chip tissue models aim to replicate the key hallmarks of the tumour microenvironment and allow for the study of dynamic interactions that occur during tumour progression. Recently, complex cancer-on-a-chip models incorporating multiple cell types and biomimetic extracellular matrices have been developed. These models have generated new research directions in engineering and medicine by allowing for the real-time observation of cancer-host cell interactions in a physiologically relevant microenvironment. However, these cancer-on-a-chip models have yet to overcome limitations including the complexity of device manufacturing, the selection of optimal materials for preclinical drug screening studies, long-term microfluidic cell culture as well as associated challenges, and the technical robustness or difficulty in the use of these microfluidic platforms. In this review, an overview of the tumour microenvironment, its unique characteristics, and the recent advances of cancer-on-a-chip models that recapitulate native features of the tumour microenvironment are presented. The current challenges that cancer-on-a-chip models face and the future directions of research that are expected to be seen are also discussed. Graphical Abstract
Abstract P2105: Store-Operated Channels Mediate Metabolic Adaptations In Activated Fibroblast During Cardiac Fibrosis
Authors: Salvatore Mancarella, Patricia Pantoja, Sheena Saxena, Amandeep Bajwa
Journal: Circulation Research (2023)

Endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR) are associated with developing fibrotic disorders in multiple organs, including the heart. Many ER resident chaperones require calcium (Ca2+) as a co-factor to mediate protein folding. Store-operated Ca2+ entry (SOCE) mediated by the Orai1 channels primarily maintains the ER- Ca2+ homeostasis. However, the role of the Orai1 channels in the modulation of ER-stress/UPR and downstream cellular processes that lead to cardiac fibrosis is not entirely understood. To investigate the role of Orai1 channels on the ER-stress/UPR signaling we utilized a multilayered approach that includes both genetic and pharmacological inhibition of Orai and a combination of long-term real-time cell imaging combined with genetically encoded sensors for several metabolites signaling. Our results showed that Orai1 expression was upregulated in the fibrotic mouse heart. Transcriptome analysis of fibrotic tissue from a fibroblast-specific Orai1 knock-out mouse model revealed the dysregulation of many genes associated with cell metabolism and collagen turnover. Pharmacological inhibition of Orai1 channel activity in cultured cardiac fibroblast decreased ER-Ca2+ and mitochondrial Ca2+ levels and was sufficient to trigger ER-stress/UPR and promote mitochondrial dysfunction. Like the in vivo fibrotic model, comparative transcriptome and pathway analysis between cells treated with Orai1 blocker (YM-58483, 48 hours) and controls identified dysregulated metabolic pathways and ER-stress/UPR signaling. Bioenergetic analysis showed that Orai1 inhibition induced an overall decrease in oxygen consumption rate (OCR), and mitochondrial membrane potential and reduced cellular ATP levels. Accordingly, we found that Orai1 loss-of-function increased glycolysis and reduced fatty acid oxidation (FAO), substantially reducing fibroblast fuel flexibility. This is a remarkable novel function of Orai1 channels because perturbations in fibroblast metabolic dynamic are the initial steps in the injury response. Our results suggest that Orai1 could be a novel target for developing treatments for fibrosis.